Honing tool

ABSTRACT

A HONING TOLL FOR ATTACHMENT TO A ROTOTABLE ADAPTER ON A HONING MACHINE WHICH INCLUDES A SLOTTED TUBULAR MANDREL FOR SUPPORTING HONING STONE ASSEMBLIES FOR RADIAL MOVEMENT BY THE CAMMING ACTION OF LINGITUDINAL RIBS ON A CAM SHAFT ROTATABLY DISPOSED WITHIN THE MANDREL, CAM MEANS ARE OPERATIVELY ASSOCIATED WITH THE CAM SHAFT WHICH ARE ACTUATED BY AN AXIALLY RECIPROCATING ACTUATING ELEMENT CONNECTED TO THE HONING MACHINE SO AS TO ROTATE THE CAM SHAFT ALTERNATELY IN OPPOSITE DIRECTIONS DURING THE STROKING OF THE ACTUATING ELEMENT TO EXPAND AND RETRACT THE HONING STONE ASSEMBLIES AS THE HONING TOOL IS ROTATED BY THE HONING MACHINE ADAPTER.

Sept. 20, 1971 c. w. MCCLURE HONING TOOL 2 Sheets-Sheet 1 Filed Sept.17, 1969 INVENTOR CHARLES W. McCLURE ATTORNEY Sept. 20, 1971 c. w.MCCLURE HONING TOOL 2 Sheets-Sheet 2 Filed Sept. 17, 1969 ATTORNEYUnited States Patent (3 Filed Sept. 17, 1969, Ser. No. 858,815 Int. Cl.B241) 9/02 US. Cl. 51338 8 Claims ABSTRACT OF THE DISCLOSURE A honingtool for attachment to a rotatable adapter on a honing machine whichincludes a slotted tubular mandrel for supporting honing stoneassemblies for radial movement by the camming action of longitudinalribs on a cam shaft rotatably disposed within the mandrel. Cam means areoperatively associated with the cam shaft which are actuated by anaxially reciprocating actuating element connected to the honing machineso as to rotate the cam shaft alternately in opposite directions duringthe strok ing of the actuating element to expand and retract the honingstone assemblies as the honing tool is rotated by the honing machineadapter.

Many types of honing machines are available today for performing ahoning operation on a hole or bore within a workpiece by utilizinghoning stones supported on a mandrel for radial movement outwardly intohoning engagement with the workpiece bore. In one type of honingmachine, such as shown in US. Pat. No. 3,152,424, a honing tool ormandrel is detachably mounted on the honing machine and rotated whilethe honing stones are alternately expanded and retracted radially bytapered surfaces or wedges on a member moved in a reciprocating mannerby an axially reciprocating drive member or feed up rod incorporated inthe honing machine. However, present day industrial practices for honedand machined articles require extremely close manufacturing tolerancesand although present day honing tools generally perform satisfactorily,it is difficult to obtain the desired degree of precision with suchpresent day honing tools to meet such industrial requirements. Forinstance, many present day honing tools utilize a plurality of honingstones arranged in circumferentially spaced relationship and the use ofcamming surfaces such as wedges of the aforementioned stones results inwear on the honing stones during use i which is not uniform. This meansthat not only is the eccentricity of the honed surface increased, butfrequent replacement of the honing stones is necessary for adherence toclose manufacturing tolerances adding considerably to manufacturingcosts from both the standpoint of the replacement costs as well as thetime and labor involved.

Other shortcomings are also found in present day honing tools. Forinstance, in the honing of blind holes or bores in a workpiece, honingtools of present day construction fail to hone the entire surface of thebore so that the honed surface terminates short of the bottom wall ofthe bore due to the engagement of the end of the mandrel supporting thehoning stones with the bottom wall. This means that either a lessfinished honed article is pro- 3,605,348 Patented Sept. 20, 1971 ducedor some supplemental operation is required to completely hone the innersurface of the workpiece bore. In addition, many present day mandrelsare not capable of smoothly and uniformly applying honing pressure tothe honing stones for radially increasing the honing diameter during thestroking action performed by the honing machine due to the variousconstructions of present day honing mandrels adding further to thedifficulty in obtaining the close tolerances and concentricity desiredfor such finished honed articles.

Accordingly, a primary object of this invention is to provide a new andnovel honing tool for attachment to a honing machine.

Another object of this invention is to provide a new and novel honingtool for attachment to a honing machine for a bore of a workpiece withinextremely close manufacturing tolerances.

A further object of this invention is to provide a new and novel honingtool which permits a plurality of honing stones to be expanded smoothlyand with uniform pressure into honing engagement with the bore of aworkpiece and which permits the honing operation to be performedthroughout the entire inner surface of the bore.

This invention further contemplates the provision of a new and novelhoning tool for attachment to a honing machine which is inexpensive andrugged in construction, which utilizes a minimum number of parts, whichpermits uniform distribution of wear over all of the honing stonesduring use and which is capable of prolonged use without breakdown.

Still another object of this invention is to provide a new and novelhoning tool which permits a honing operation to be performed at a highproduction rate on the bore of a workpiece with a resultant honedsurface characterized by a total absence of eccentricity and extremelyclose manufacturing tolerances.

Other objects and advantages of the invention will become apparent fromthe following description taken in connection with the accompanyingdrawings.

In general, the object of this invention and other related objects areaccomplished by providing a honing tool which includes a tubular mandrelhaving a central bore in which is rotatably mounted a cam shaft having aplurality of longitudinally extending, circumferentially spaced,upstanding ribs, adjacent one end of the mandrel, the mandrel beingmounted on a housing having a central bore which is positioned forrotation in an adapter of a honing machine. The ribs are provided withcamming surfaces engageable with the inner ends of a plurality of honingstone assemblies positioned for sliding radial movement in slotsprovided in the mandrel. An axially slidable actuating element ispositioned in the housing'bore for attachment to the stroking means ofthe honing machine and cam means are provided on the actuating elementand the other end of the cam shaft for rotating the cam shaftalternately in opposite directions as the actuating element is strokedfor expanding and retracting the honing stone assemblies alternatelyduring the rotation of the honing tool by the adapter.

The novel features which are believed to be characteristic of theinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as to its organization and method ofoperation may be best understood by reference to the followingdescription taken in conjunction with the accompanying drawings inwhich:

FIG. I is a side elevation view, partially in section, of a honing toolconstructed in accordance with the invention mounted in an operatingposition;

FIG. 2 is an enlarged sectional view of the honing tool of FIG. 1;

FIG. 3 is a sectional view taken substantially along line 33 of FIG. 2in the direction of the arrows;

FIG. 4 is a sectional view of a portion of the tool of FIG. 2 with theparts in another position;

FIG. 5 is an enlarged end view of a portion of the honing tool of FIG.2;

FIG. 6 is an enlarged sectional view taken substantially along line 6-6of FIG. 2 in the direction of the arrows;

FIG. 7 is a view similar to FIG. 6 showing the parts in the positioncorresponding to FIG. 4;

FIG. 8 is a side elevation view of a portion of the honing tool of FIG.2; and

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. 2in the direction of the arrows.

Referring now to the drawings and to FIG. 1 in particular, there isshown a honing tool constructed in accordance with the invention whichis designated generally by the letter T. As is well known, the honingtool T is arranged to be mounted in the bore 11 of a holder or adapter12 of a honing machine of any well known construction. The adapter 12 ispositioned on the forward end of a rotatable shaft 13 journaled in thehoning machine frame 14 as shown and described in the aforementionedpatent. As described in this patent, the shaft 13 is rotatably driven bysuitable means (not shown) incorporated in the associated honing machineand the honing machine includes an axially reciprocating feed-up meansor drive member 16 driven by suitable means (not shown) alsoincorporated in the honing machine for axially reciprocating or strokingthe drive member as indicated by the double arrow I of FIG. 1. It shouldbe understood, however, that any suitable type of honing machine may beutilized with the honing tool T of the invention and reference is madeto the honing machine of the aforementioned patent by way of exampleonly.

As is well known, the honing tool T is of the type for performing agrinding or honing operation on the bore 18 of a workpiece designatedgenerally in FIG. 1 by the letter W, the outer end of the honing tool Tbeing arranged to be inserted within the workpiece bore 18 as shown inFIG. 1.

Referring now to FIG. 2, the honing tool T includes a housing 21 havinga central bore 22 which is arranged to be received within the honingmachine adapter 12 and secured thereto for rotation therewith by meanssuch as a set screw 23' engageable with a flat 24 on the adapter 12. Atubular mandrel 26 is provided having a central bore 27 and an enlargedinner end portion 28 which is arranged to be accommodated within arecess 29 of the housing 21 so that the mandrel 26 projects forwardlytherefrom for insertion of its forward end 26a within the workpiece bore18. The mandrel 26 is preferably detachably secured to the housing 21 bymeans of a set screw 31 threadedly accommodated within a tapped hole 32in the housing 21, the inner end of the set screw 31 being provided witha dowel or pin 33 accommodated with a radial passage 34 in the enlargedinner end portion 28 of the mandrel 26.

A plurality of circumferentially spaced, longitudinally extending slots36-38 are provided in the mandrel 26 adjacent its forward or outer end26a which open into the mandrel central bore 27 and which are preferablyinterrupted intermediate their ends by bridging mandrel portions 41-43respectively for a purpose to be explained hereinafter.

In the illustrated embodiment three of such slots 36-38 are providedwhich are uniformly spaced circumferen- As the slots 36-38 areinterrupted by the bridging portions 41-43, the honing stone assembly 44which is accommodated in each slot is therefore formed of twolongitudinally aligned segments as shown best in FIG. 2, the shortersegment being designated by the numeral 44 and the longer segment by thenumeral 44". It will be noted that in the preferred embodiment, each ofthe slots 36-38 are provided with longitudinally spaced arcuate recesses37a-38a respectively on opposite sides which are arranged to accommodatesimilarly spaced, lateral projections or ears 49 on the honing stoneholders 46 when the honing stone assemblies 44 are positioned within theslots 3'6-38. As both the ears 49 and recesses 36a-38a extend radially,there is no interference with the free sliding movement of the honingstone assemblies 44 but longitudinal tilting or canting of the stoneassemblies in the slots is prevented.

A cam shaft 51 is positioned for axial rotation in the mandrel bore 27with its outer end 51a adjacent the mandrel outer end 26a and its innerend extending within the housing bore 22. A plurality ofcircumferentially spaced, longitudinally extending upstanding ribs 56-58are provided on the cam shaft 51 which extend from adjacent the camshaft outer end 51a in underlying relationship with the mandrel slots36-38 respectively. One side of each of the ribs 56, 57, 58 is providedwith an arcuate camming surface 56a, 57a, 58a respectively for cammingengagement with the respective bearing surfaces 46a on the inner end ofhoning stone assemblies 44 as shown best in FIG. 6. As shown in FIGS. 2,4 an annular groove 60 is provided on the periphery of the cam shaft 51which receives the inner end of the pin 33 on the set screw 31 in theassembled condition of the tool T so as to prevent axial movement of thecam shaft 51 as the cam shaft is rotated. The inner end of the cam shaft51 includes a portion of enlarged diameter 61 which extends within thecentral bore 62 of an actuating element 63 slidably positioned withinthe central bore 22 of the housing 21.

Means are provided for connecting the actuating element 63 to thereciprocating drive member 16 of the honing machine. More specifically,a countersunk bore 64 is provided in the end of the actuating element 63adjacent the honing machine for snugly accommodating an end plate 66which is provided with an axially extending hook 67 preferably formedintegrally therewith and arranged to be detachably coupled to a similarhook 68 formed on the adjacent end of the drive member 16 in the form ofa bayonet connection or the like. The end plate 66 is retained in therecess 64 by suitable means such as a set screw 68 having a pin 69 onits inner end and threadedly engageable as shown, with a tapped radialhole 71 in the actuating element 63 for retaining engagement of the pin69 within a recess 72 in the end plate 66.

Means are provided for guiding the actuating element 63 for axiallyreciprocating, sliding movement in the housing central bore 22. Morespecifically, a longitudinally extending slot 73 is provided in theouter periphery of the actuating element for accommodating the inner endportion of a guide pin 74 secured by press fitting or the like in aradial hole 76 in the side wall of the housing 21.

Cam means are provided on the actuating element 6 3 and the portion ofenlarged diameter 61 on the cam shaft 51 for alternately rotating thecam shaft 51 in one direction during the axial movement of the actuatingelement 63 in one direction for camming the honing stone assemblies 44radially outward to increase the honing diameter of the honing stones 47and for rotating the cam shaft 51' in the other direction during theaxial movement of the actuating element 63 in the other direction topermit thehoning stone assemblies 44 to be moved radially inward forreducing the honing diameter of the honing stones 47. More specifically,the enlarged portion 61 which is of cylindrical shape is provided withat least one and preferably two helical slots 81, 82 arranged indiametrically opposed relationship somewhat in the form of a drum orcylinder cam for receiving follower pins 83, 84 also arranged indiametrically opposed realtionship and mounted by press fitting or thelike in radial holes 86, 87 respectively in the wall of the actuatingelement 63.

The honing tool T also includes means for supplying a lubricating fluidto the interior of the workpiece W for lubricating the surface of theworkpiece bore 1-8 during the honing operation. More specifically, alubricating fluid is fed in the direction of the arrow L of FIG. 2 fromsuitable means (not shown) within the associated honing machine into thebore 22 of the housing 21 for subsequent introduction into the actuatingelement bore 62 through a passage 91 in the end plate 66, suitablesealing means for the housing 21 being provided by an O-ring 92positioned in an annular groove 93 in the outer periphery of the housing21. The lubricating fluid then flows through an axial passage 94 in thecam shaft 51 and through radial passages 96, 97 and radial ports 98, 99in the cam shaft 51 and mandrel respectively out wardly into the bore 18of the workpiece W.

In the operation of the honing tool of the invention, the tool T ismounted in the operating position by inserting the housing 21 into thehoning machine adapter 12 and the set screw 23 tightened down againstthe housing flat 24 to retain the tool T on the adapter 12 as shown inFIGS. 1, 2. The hook 67 on the cam shaft 51. is attached to the hook 68on the drive member 16-. Operation of the honing machine axially rotatesthe housing 21 together with the mandrel 26 and cam shaft 51 with theouter end of the mandrel being inserted within the bore 18 of theworkpiece W to be honed. At the same time, the axial reciprocation ofthe drive member 16 by the honing machine reciprocates the actuatingelement 63 axially, rotation of the actuating element 63 being preventedby the pin 74 extending within the actuating element slot 73. Theactuation of the drive member 16 may be initiated by any suitable meanssuch as foot pedal or the like under the control of the operator. Theaxial movement or stroking of the actuating element 63 moves theactuating element from a rearward position such as shown in FIG. 4 withthe actuating element pins 83, 84 traveling in the helical groove 81,82. of the cam shaft portion 61 to rotate the cam shaft in one directionso that the longitudinal ribs 56-5 8 are moved to the position of FIG. 7permitting the honing stone assemblies 44 to retract and decrease thehoning. diameter of the stones 47 Forward movement of the actuatingelement 63 from the position of FIG. 4 to the position of FIG. 2 rotatesthe cam shaft 5 1 in the opposite direction so that the cam surfaces56a-58a on the ribs 56-58 engage the inclined surfaces 46a on the honingstone assemblies 44 smoothly and uniformly camming the stone assemblies44 radially outward into the position shown in FIG. 6 thereby increasingthe honing diameter of the stones 47. During the honing operation, thecam shaft 51 is rotated alternately in opposite directions with theaxial reciprocation of the actuating element 63 and lubricating fluid issupplied to the interior of the workpiece W through the various passagesand chambers described above.

It has been found in practice that the stroke or axial movement of theactuating element 63 should be no less than one inch although it shouldbe understood that any desired stroke length may be employed inaccordance with the honing requirements. Also, it has been found inpractice that a cam shaft rotation of approximately 60 between thepositions of FIGS. 6, 7 produces satisfactory results in the operationof the invention and, if desired, the ribs 5658 and honing stoneassemblies 44 may have their camming surfaces reversed so that thehoning stone assemblies 44 are expanded radially outward in the oppositedirection of rotation of the cam shaft 51 from that shown in theillustrated embodiment.

As shown in the drawings, the slots 36-38 in the mandrel 26 are open attheir ends adjacent the mandrel end 26a to thereby permitting blind holehoning so that the entire surface of the workpiece bore .18 may be honedwith the tool T of the invention. In order to maintain thecross-sectional shape of the portion of the mandrel 26 adjacent the end26a, an insert or end cap 101 is suitably secured by welding or the likeWithin the mandrel bore 27 at the end 26a of the mandrel therebypreventing flexing of the mandrel portions between the slots adjacentthe mandrel end 26a.

While there has been described What at present is considered to be thepreferred embodiment of the invention, it will be understood by thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention.

Having thus described the invention, what is claimed is:

1. A honing tool for attachment to a honing machine of the type having arotatably driven adapter and an axially reciprocating drive membercomprising, in combination, a housing having a central bore, means formounting said housing on said honing machine adapter for rotationtherewith, a forwardly extending tubular mandrel having a central boremounted at one end on said housing and the other end arranged to beinserted into the bore of a workpiece to be honed, a plurality ofcircumferentially spaced, longitudinally extending slots in said tubularmandrel adjacent said mandrel other end and opening into said mandrelcentral bore, a honing stone assembly including a. honing stone mountedin each of said slots for freely slidable, radial movement, an actuatingelement having a central bore and positioned in said housing centralbore, means for guiding said actuating element for axially reciprocatingsliding movement in said housing central bore, means for connecting saidactuating element to said honing machine drive member, a cam shaftpositioned for axial rotation in said mandrel central bore and having aninner end portion extending within said actuating element central bore,a plurality of circum ferentially spaced, longitudinally extending,upstanding ribs on said cam shaft adjacent the outer end of said camshaft and in underlying relationship with said mandrel slots, each ofsaid ribs having a camming surface on one side engageable with the innerend of one of said honing stone assemblies, cam means on said actuatingelement and said cam shaft inner end portion for rotating said cam shaftin one direction during the axial movement of said actuating element inone direction for camming said honing stone assemblies radially outwardto increase the honing diameter of said honing stones for honingengagement with said workpiece bore and for rotating said cam shaft inthe other direction during the axial movement of said actuating elementin the other direction to permit said honing stone assemblies to bemoved radially inward for reducing the honing diameter of said honingstones.

2. A honing tool in accordance with claim 1 wherein each of said honingstone assemblies comprises a holder and a honing stone secured to theouter end surface of said holder and wherein the inner end of saidholder is provided with an inclined surface for camming engagement withsaid camming surface on the associated rib.

3. A honing tool in accordance with claim 1 wherein said plurality ofcircumferentially spaced ribs comprise three of said ribs arranged in aspaced-apart relationship and wherein said plurality of mandrel slotscomprise three of said slots arranged in a 120 spacedapart relationship.

4. A honing tool in accordance with claim 3 wherein one end of saidslots in said mandrel open into said mandrel other end and including anend cap fixedly secured to said mandrel within said mandrel bore at saidmandrel other end to maintain the cross-sectional shape of the portionof said mandrel adjacent said other end.

5. A honing tool in accordance with claim 4 including a plurality ofcircumferentially aligned arcuate segments on said mandrel eachextending transversely of one of 7 said slots and intermediate the endsof said slot to define on opposite side thereof a pair of longitud'mallyaligned slot portions and a honing stone assembly in each of said slotportions.

6. A honing tool in accordance with claim 3 wherein said cam meansinclude at least one helical slot on the outer periphery of said camshaft inner end portion and at least one radially extending follower pinon said actuating element having an inner end portion slidablyaccommodated within said helical slot for rotating said cam shaftalternately in opposite directions during the axial reciprocatingmovement of said actuating element.

7. A honing tool in accordance with claim 6 wherein a pair of saidhelical slots arranged in diametrically opposed relationship areprovided on the said cam shaft inner end portion and wherein a pair ofsaid follower pins are provided in diametrically opposed relationship onsaid actuating element each arranged to be accommodated in one of saidhelical slots.

8. A honing tool in accordance with claim 7 wherein said guide meansinclude a longitudinally extending slot on the outer periphery of saidactuating element and a radially extending pin on said housing having aninner end portion slidably accommodated with said slot on said actuatingelement for guiding said actuating element for said axiallyreciprocating sliding movement in said housing bore.

References Cited UNITED STATES PATENTS 1,981,258 11/19'34 Wagner 51-3471,926,835 9/19'33 Cook 51-347 HAROLD D. WHITEH'EAD, Primary Examiner US.Cl. X.R. 51339, 347

